Proposal Information for 2009A-0152

CoI: J. A. Sellwood, Rutgers UniversityCoI: Kristine Spekkens, Royal Military College of Canada

Title: Cold Dark Matter and the Structure of Spiral Galaxies

Abstract: We propose to obtain deep BVRI imaging of the accessible targets in a large sample of nearby, normal spiral galaxies for which multi- wavelength velocity fields will also be derived. Observing time was allocated through NOAO during semester 2008A to carry out this imaging. However, poor weather conditions, scheduling constraints and a service observing error prevented us from completing our target list, prompting a resubmission of this proposal. Many of the remaining sample targets were imaged in 2007B, and NOAO time has been allocated in 2008B to complete observations of this portion of the sample. The requested broadband imaging is essential for characterizing the stellar morphology, baryonic mass-to-light ratio and disk geometry in each target, while spectroscopic observations obtained at other facilities probe the total mass distribution therein. Detailed mass models of the resulting photometry and kinematics will quantify the importance of asymmetries and projection effects on the dark matter halo profiles inferred for each system, and self-consistent realizations of the optimal fits will mitigate the degeneracy between the dark and luminous components. Our observational program will thus yield tight constraints on the halo profiles of nearby spirals in a key test of the canonical Cold Dark Matter paradigm on galaxy scales.